Preoxygenation in the elderly: Comparison of three minutes and four deep breath tecniques

INTRODUCTION: Preoxygenation with 100% O2 prior to induction is a standart procedure in anesthesia practice.With preoxygenation, alveolar washout of air mixture in functional residuel volume provides higher alveolar oxygen concentration up to 100% which leads to increased alveolar oxygen reserve, so during apnea, time to desaturation levels are delayed We studied two different preoxgenation methods in elderly patients, three minutes and four deep breaths to detect which one is more efficient in this patient groupMETHODS: 30 patients over 60 years included in the study. ECG, TA, HR and SpO2 were monitorised.Data were recorded before preoxygenation,after induction,after intubation,and when SpO2 reached to 93%.Blood gas analysis also performed at the same time points.Time to reach to SpO2 levels of 97%,95%,93% were also recordedIn GrI(n=15), patients were asked to breath normally for three minutes, after the mask is tightly applied to the patients face.In GrII(n=15), they asked to take four deep breaths when ordered by the anaesthesist, then breath normallyPreoxygenation, ınduction and intubation were performed.The distal end of the tube was left open, the patients were not ventilated untıl SpO2 levels reach to 93%, then they ventilated with 100% oxygen and the study endedRESULTS: The study was completed with 29 patients.There were no difference in demographic variables and Htc levels and time to apnea(p>0,05).Mean age was 65,8years(61-76)in GrI and 65,2years (60-74) in Gr II.The hearth rates were different in two groups at the time points of SpO2 97%, 95%, and 93% and time to reach these desaturation points were significantly different in four deep breath group of patients (p<0,001;p<0,01,p<0,05).DISCUSSION AND CONCLUSION: The physiological changes effect lung capacities and reserves in elderly patients.We conclude that, as the effectiveness of vital capacity breaths were decreased in these patients, three minutes of tidal breats should be the method of choice for preoxygenation